PB2547: ESTIMATING HEALTH-RELATED QUALITY OF LIFE IN ADULT PYRUVATE KINASE DEFICIENCY: A TIME TRADE-OFF UTILITY STUDY
Authors: Sara Higa, Gin Nie Chua, Anna-Katrine Sussex, Andrew Lloyd, Junlong LI, Parija Patel, Susan Morris, Erin Zagadailov
Journal: HemaSphere (2023)

Topic: 28. Enzymopathies, membranopathies and other anemias Background: Pyruvate kinase (PK) deficiency is a rare, inherited hemolytic anemia which may lead to serious complications such as iron overload and pulmonary hypertension. Health-Related Quality of Life (HRQoL) utilities are needed to support economic evaluations to assess the value and impact of treatments. However, utilities are typically derived from generic patient-reported outcome (PRO) measures (e.g., EQ-5D) which may be insensitive to unique aspects of PK deficiency that reduce HRQoL. A recently published study showed an average utility of 0.88 (measured 0-1 scale; 0: death, 1: full health) in adult patients with PK deficiency, similar to that of the general population. As patients with PK deficiency are born with the disorder, they may under-report its impact due to adapting to their condition (i.e., habituation). Assessing HRQoL in patients with PK deficiency using the general population’s perception of the disease may generate more accurate utilities, as they are not conditioned to habituation. Aims: To estimate utilities for health states associated with PK deficiency as evaluated by the general population. Methods: To elicit utilities in PK deficiency, vignettes (scenarios characterizing various health states experienced by patients) were developed with input from a literature review, symptoms and impacts from disease-specific PRO data from two phase 3 trials in PK deficiency, and 1:1 online interviews with two hematologists and three adult patients with PK deficiency. Six vignettes were created to describe health states stratified by transfusion status and hypothetical response to an intervention. Response health states were described as having lower levels of severity and/or frequency of symptoms (e.g., fatigue, shortness of breath, jaundice, and bone pain) and less impact on HRQoL (e.g., physical, work, social, and emotional) compared to non-response health states. The final vignettes were evaluated via online interviews with demographically representative participants from the general public in the UK and France who were recruited online (panels and advertising). Utilities were elicited during these interviews using the time trade-off (TTO) method where participants chose between a shorter life in perfect health or living longer in one of the health states. Utilities were summarised descriptively (mean, SD) and compared between health states using the Wilcoxon test. Results: 200 participants evaluated the vignettes (52% female; mean age 42.5 years). TTO utilities were similar for the UK and France across all health states. Utilities in the non-response health states ranged from 0.407 to 0.829 and 0.417 to 0.766 in the UK and France, respectively. Overall, mean utility values were significantly higher in response health states (p<0.001) compared to non-response [Table 1]). Summary/Conclusion: Significantly higher utilities for treatment response health states compared to non-response suggests that participants valued states with less PK deficiency-related symptoms higher than a life with more severe or frequent symptoms that negatively impact daily life. TTO utilities elicited from the general population were descriptively lower than previous estimates from generic instruments in patients with PK deficiency. These results generated from a population not habituated to the condition indicate that symptoms of PK deficiency have a higher impact than patients may perceive and further validate that generic instruments completed by patients who are habituated by the condition may not sufficiently capture HRQoL in PK deficiency.Keywords: Quality of life, Hemolytic anemia, Clinical outcome, Pyruvate kinase deficiency